Quick plumbing question before i replunb my tank

[John08007]

I had the smaller current usa dc return pump plumbed with 3/4" pipe. I was unhappy with the flow even with the pump maxed out so I just swapped it out with the largest current usa pump. Still using the same 3/4" pipe that splits to 2 return nozzles at my tank. The flow seems to have increased some but I think it should be more. Do you think I would see a big advantage to run 1.25" pipe up and then split to 2x 3/4" returns at the very end? I believe this pump puts out over 3k gal, not sure if that's taking my 6' head into consideration.

 

[sunken3]

yes.. there is science behind it (but i don't know it).. the longer your line is with larger pipe the better flow you will get at the end. at some point you will need to ensure that your overflow can handle the additional water and not overflow the actual tank.

 

[John08007]

The pump is dc, I can turn it down if I need to. I also have a herbie overflow, I can open the valve on my drain to allow more flow to the sump. My assumption is that the 3/4" pipe is adding too much resistance and limiting the flow.

 

[sunken3]

very likely.. i had a RODI system that i originally plumb from the source with 1/4" water line.. and had very little pressure (it was a long line).. i replumbed it with 1/2" pvc from the source to a few feet from the RODI where it converted to 1/4" hose.. even though the last few feet was 1/4" the pressure was significantly different.. it must be that the "resistance" is much shorter.

 

[Skynyrd Fish]

Yes run the 1.25” pipe and split. You will double your flow. It has to do with friction and back pressure. I’m not an engineer, there is more to it than this.

 

[mehaffydr]

3/4" pipe with moderate pressure can flow a max of 1400GPH and by moderate I am talking 100PSI. I am certain the the current pump has no where near that pressure so YES 2ea 3/4" pipes are not really adequate to get the most out of your pump go with the larger pipe it will help.

 

[CMMorgan]

It will absolutely help. Think of it like putting your finger over the end of the hose when you wash the car.

 

[ca1ore]

Don’t think the flow will double, but upsizing the pipe diameter will certainly help. Can you split 1 1/2” into two 1” .... that will help too.